1. Field of the Invention
The invention relates to a sheet feeder and a scan apparatus, and more particularly to a sheet feeder and a scan apparatus with a sheet-stopping function independent of movement of a pick-up mechanism.
2. Related Art
At present, image processing apparatuses, such as multi-function peripherals or scanners, are aimed to be reduced in volume and furnished with stylish industrial design. Thus, a horizontal supply tray may be designed to complement the functionality of the image processing apparatuses in order to reduce the size of the apparatuses or to achieve the special exterior requirement, and a pick-up mechanism for picking up the sheet from the supply tray may be added as well.
However, the pick-up mechanism has to work in conjunction with a sheet-stopping mechanism to prevent the sheets, which are not to be processed at the moment, from entering the sheet passageway. The conventional sheet-stopping mechanism is usually linked with the pick-up mechanism or driven by an independent actuator, and the conventional sheet-stopping mechanism has to be moved to an utmost point. Usually, a sensor is disposed to ensure that the execution of the sheet-stopping mechanism is certain and precise, and a driving torque of greater magnitude is required to move the sheet-stopping mechanism to the utmost point. If the sheet-stopping mechanism is driven by an independent actuator, the addition of the actuator will increase the production cost. If the sheet-stopping mechanism is linked with the pick-up mechanism, the sheet-stopping mechanism and the pick-up roller of the pick-up mechanism affect each other, and the variables to be considered in the design phase get more so that the design becomes complicated. In addition, a high-power driving motor has to be used. Furthermore, the size of the assembly of the conventional pick-up mechanism and the sheet-stopping mechanism cannot be effectively reduced.